This invention relates to an improved system for removing accumulated oil from a basin, and more particularly, to a belt skimmer type oil removal unit.
A belt skimmer basically comprises an endless belt loop which is continuously revolved by a rotary drum, with the bottom loop of the belt submerged in the basin containing the oil to be removed. The oil adheres to the belt and is carried up by the belt into the unit and around the drum. The belt then passes between blades which scrape the oil off the belt.
When the belt is coated with oil, it becomes very slippery and tends to slip on the rotating element. The belt does not maintain its travel velocity relative to the rotating element, and often the belt stops. This results in at least erratic operation and inefficient oil removal. Another problem results from the oil running back down the belt into the basin, because the belt is operating too slowly.
In order to maintain the proper, constant velocity of the belt, one prior art type system uses a weighted or tension device on the bottom loop that is submerged in the water. However, this can cause jamming of the belt below the water due to improper alignment or loss of the separate device because of foreign debris. It can also cause difficult installation problems in many cases.
Another prior art system passes the belt between a roller arrangement and the rotating element to squeeze the belt in between the two. The disadvantage of this expedient is that it tends to squeeze the oil back down the belt into the basin before it gets to the scrapers.
It is, therefore, an object of the present invention to provide a system for maintaining a proper and constant velocity of the belt during the belt skimming operation.
Another object of the present invention is to properly remove the oil from the moving belt in a belt skimming operation.
Other objects and advantages of the present invention will become apparent as the description proceeds.